Sigmund Riefler (9 August 1847 – 21 October 1912) was a German physicist, inventor and precision clockmaker.

[3] In 1876 after the death of his father, he took over the firm of Clemens Riefler with his two brothers, Adolf and Theodor.

Sigmund worked mainly on new developments in the area of drawing instruments and precision clocks, while his brothers handled the technical, sales and management of the company.

In 1878 he settled in Munich, to be in contact with the local scientific community.

Monroe mentions Sigmund Riefler in the "One Night Stand" episode in Season 3 of Grimm.